Improved Ionic Conductivity and Li Dendrite Suppression Capability toward Li₇P₃S₁₁-Based Solid Electrolytes Triggered by Nb and O Cosubstitution

It is still a big challenge to simultaneously enhance the ionic conductivity, dendrite suppression capability, and interfacial compatibility of sulfide solid electrolytes. In this work, a novel Li 7 P 2.88 Nb 0.12 S 10.7 O 0.3 solid electrolyte is prepared via Nb and O cosubstitution of glass-ceramic Li 7 P 3 S 11 . This sulfide-based electrolyte possesses a high ionic conductivity (3.59 mS cm –1 ) at 298 K, improved critical current density (1.16 mA cm –2 ), and excellent interfacial compatibility between the sulfide electrolyte and Li 2 S active material. The improved electrochemical stability of the sulfide solid electrolyte against metallic lithium is attributed to the formation of Nb and Li 2 O at the interface, which can induce uniform Li deposition and prevent further side reaction. The all-solid-state Li/Li 2 S batteries based on this electrolyte exhibit remarkably enhanced cycling stability and rate performance.